when should i change the catalytic ?...after how much milage..

 

I have never seen anyone replace the catalytic converter as a preventative measure. It fails, throws a Check Engine light....you replace it. Cat's might even come with a 10 year warranty as it is part of the emissions system?

 

but i smell something strangeeach time a stop the engine andall said that is the catalytic smells, is that true...